Intrathecal but not intravenous opioids release adenosine from the spinal cord.
D000241:Adenosine / Q000134:cerebrospinal fluid*; D000293:Adolescent; D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage*; D017288:Pain Threshold / Q000187:drug effects; D010880:Piperidines / Q000008:administration & dosage*; D000077208:Remifentanil; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
D000701:Analgesics, Opioid; D010880:Piperidines; D009020:Morphine; D000241:Adenosine; D000077208:Remifentanil; D005283:Fentanyl